Arrangement for closing off fluid passages

ABSTRACT

An arrangement and method for closing off fluid passages is disclosed. The arrangement includes first and second closure members inserted one behind the other in the fluid passage, the second closure member slidably fit into the passage with a clearance and positioning against a sealing shoulder in the fluid passage so that abraded particles caused by press fitting of the first closure member behind the second closure member can not get into the fluid passage.

This is a continuation of application Ser. No. 08/089,414, filed on Jul.9, 1993, U.S. Pat. No. 5,295,293.

BACKGROUND OF THE INVENTION

The present invention relates to a device for permanently closing offfluid passages formed in a housing.

Arrangements for permanently closing off fluid passages in hydraulic andpneumatic connectors and housings find many applications and hence arerequired in large quantities. Closing devices of the above-mentionedtype are designed both as force-locking and form-locking elements.Screw-type, bayonet-type and press-type closing arrangements aregenerally known and widely employed which, admittedly, permit asatisfactory closure of the fluid passages. However, these devicesentail disadvantages due to their complicated construction and/orassembly.

For instance, it is known from the illustration of German publishedpatent application DE-OS 37 29 216 to block a fluid passage in a valveblock by simply press fitting of a ball into an enlarged portion of thepassage, and thereafter caulking the ball in place by upsetting of thepassage wall which expedient is reliable and low in cost. This means ofclosing off a passage has the shortcoming that material is abraded bycontact of surfaces of the ball with the surface defining the fluidpassage, particularly for relatively soft valve block material duringthe press fitting. The abraded particles and chips can get into thefluid passage. In consequence of this undesirable effect, thoroughrinsing operations are needed in order to eliminate the particles tosafeguard the operability of solenoid valves or other sensitivecomponents in the valve block assembly in later use.

Admittedly, it is already known to use so-called "king expanders",wherein a sleeve-shaped supporting body provided with claws is firstinserted into the passage to be closed off, a ball is thereafter pressedinto the supporting body in order to accomplish the necessary retainingforce by expanding the supporting body. However, this closure mechanismstill requires a significant assembly effort, and there is still somerisk of abrasion particles entering the fluid passages. Also, themanufacturing costs are not minimized. Thus, there is a need for aparticularly simple and absolutely reliable closing device.

Therefore, it is an object of the present invention to devise a closingarrangement which lends itself to ease of manufacture and absolutelyreliably closes off a fluid passage with minimal mounting effort andwithout any possibility of releasing abrasion particles into the fluidpassage.

SUMMARY OF THE INVENTION

The object of the invention is achieved in a surprisingly simple fashionby an arrangement according to the invention for closing off a fluidpassage comprising a first and second closure members inserted one afterthe other in an enlarged portion of the fluid passage.

The first closure member is a press fit in relation to the enlarged ductportion and bears against the previously inserted second closure member,which is loosely fit into the enlarged fluid passage portion and is heldagainst a sealing seat shoulder formed by the transition between thefluid passage and the enlarged portion thereof.

The overall dimension of the second closure member is slightly smallerthan the overall dimension of the first closure member, the secondclosure member being provided with a clearance fit in relation to theenlarged fluid passage portion in order to be freely moved into abutmentagainst the sealing surface of the shoulder.

A cavity is defined between the first and second closure members whichserves to accommodate any particles abraded by press fitting of thefirst closure member, the particles prevented from entering the fluidpassage by the sealing action of the second closure member against theshoulder.

It is particularly advantageous to use as closure members two precisionsteel balls of standard sizes which are arranged directly one behind theother in the enlarged portion of the fluid passage, the space betweenthe balls permitting a sufficiently large cavity for receiving abradedparticles.

Further advantages and features of this invention can be gathered fromthe description of an embodiment set out herein.

DESCRIPTION OF THE DRAWING

The FIGURE shows an arrangement according to the invention for closingoff a fluid passage depicted on an enlarged drawing scale.

DETAILED DESCRIPTION

The FIGURE displays in cross-section the enlarged portion 3 of a fluidpassage 6 formed in the housing 8. This enlarged passage portion 3receives two aligned metal closure members 1, 2 here taking the form ofsteel balls The first closure member 1 is pressed into the enlargedportion 3, held against the previously inserted second closure member 2.

A shoulder 5 is formed by the transition between the enlarged portion 3and the main portion of the fluid passage 6, and the shoulder 5 forms asealing seat or surface 7, on which the second closure member 2 is heldin abutment by the pressure exerted by the first closure member 1. Theseating of the second closure member 2 is intended to seal the fluidpassage 6 against any escape of fluid. There is a loose or slidableclearance fit of the second closure member 2 in the enlarged portion 3,so that the pressure exerted by the first closure member 1 on the secondclosure member 2 insures that the sealing engagement of the secondclosure member 2 with the conical sealing seat surface 7 is accomplishedto isolate the pressure fluid duct 6 and the cavity 4 enclosed in theenlarged duct portion 3 between the two closure members 1, 2.

As shown in the FIGURE, as a final step, the balls 1, 2 are "caulked",i.e., a tool (not shown) drives the material of the housing about theperimeter of the enlarged bore portion 3 so as to upset and reduce thediameter thereof in the region "A" behind the closure member 1 on theother side from the second closure member 2, the material driven againstthe other side of the one closure member 1 as shown to provide anadditional fixing of the one closure member in the enlarged passageportion 3. The resulting tool impression is seen at "B".

The use of balls as closure members 1, 2 affords a simple centering and,simultaneously, good sealing of the second closure member 2 on thesealing seat surface 7 as well as reliable fixing of the first closuremember 1 in the enlarged duct portion 3.

The cavity 4 defined by the boundary surfaces of the two closure members1, 2 and the enlarged passage portion 3 can thus receive the solidparticles abraded by pressing in of the first closure member 1. However,contamination of the pressure fluid duct 6 adjoining to the enlargedduct portion 3 is precluded by the isolating effect created by holdingthe second closure member on the sealing seat surface 7. At the sametime, the in series arrangement of the two closure members 1, 2 providesdouble protection against pressure fluid leakage so that there isdefinitely a reliable sealing of the pressure fluid passage 6 in thehousing 8.

To render the idea of our invention more distinct, the embodiment showsthe combination of two closure members 1, 2 designed as ball elements.Other analogous embodiments relating to the design of the closuremembers 1, 2 are possible, although not here illustrated.

I claim:
 1. An arrangement for permanently closing off a fluid passagein a housing comprising an increased diameter portion formed in saidfluid passage creating a shoulder therein, a steel first closure memberand a second closure member, said second closure member having adiameter smaller than said increased diameter portion of said fluidpassage to be slidably fit in said enlarged portion of said fluidpassage and engaged against said shoulder to seal said fluid passage,said steel first closure member having a larger diameter than saidenlarged fluid passage portion and permanently press fit in saidenlarged fluid passage portion and thereby immovably fixed abuttingagainst said second closure member and holding said second memberagainst said shoulder, said first closure member harder than thematerial of said housing such that particles may be abraded from saidhousing as said first closure element is press fit into said enlargedportion of said fluid passage, said first and second closure membersconfigured to define a cavity space therebetween with said membersabutting, whereby said second closure member creates a seal preventingentry of any abraded particles into said fluid passage.
 2. Anarrangement for closing off a fluid passage as claimed in claim 1,wherein said first and second closure members both comprise steel balls.3. An arrangement for closing off a fluid passage as claimed in claim 1,wherein said shoulder defines a conical sealing seat.
 4. An arrangementfor closing off a fluid passage as claimed in claim 1, wherein thematerial of said housing defining said fluid passage is deformedinwardly against said first closure element to provide an additionalfixing of said first closure element abutting against said secondclosure element.